25 years of the Hubble Space Telescope

Among its many discoveries since 1990, Hubble has revealed the age of the universe to be about 13 to 14 billion years, much more accurate than the old range of anywhere from 10 to 20 billion years. Hubble played a key role in the discovery of dark energy, a mysterious force that causes the expansion of the universe to accelerate. Seen is the Hubble Space Telescope from space shuttle Atlantis

This is an image released by Hubble as its anniversary picture

But the journey was not a cakewalk for the giant space machine. Its launch was mired in controversies soon after NASA realised that a mirror had been wrongly grounded in the telescope and the cost to replace that would be huge. It was replaced by a few scientists in what was one of the longest spacewalks in history of mankind. Hubble being launched in 1990

Between 1993 and 2009, the telescope has been serviced five times to replace old equipment and make repairs. But in 1999, engineers discovered that a small connection in telescope’s Power Control Unit, also called its heart, had loosened over time and was causing issues with the unit’s batteries. This again gave birth to speculations that the telescope might be nearing its end. It took the NASA team three years to repair the damage. This is a picture of the telescope during one of its service missions

The Hubble Space Telescope has completed its 25 years in the lower Earth orbit. In all these years, the telescope has sent some stunning pictures that have not only helped us not only admire the space but also better understand the world that lies beyond solar system. Seen in this picture is the telescope when it was first deployed into space by shuttle Discovery

Hubble has captured some jaw-dropping images of galaxies. This is galaxy M51 with old stars in its yellowish central core and the older ones in the curving spiral arms. The picture was taken in 2005

The project is a joint venture of National Aeronautics and Space Administration (NASA) and European Space Agency (ESA). This is a picture of Hubble Space Telescope’s primary mirror which has a diameter of 8 feet. The picture was captured in 1979, years before the telescope was launched into space

This is a picture of a rare look of three of Jupiter's largest moons--Europa, Callisto, and Io--parading across the banded face of the gas-giant planet. The moons in these photos have distinctive colors. Picture was captured by the Hubble Space Telescope in 2015